docs: def Buzzelli_2008(Re, eD):
      r'''Calculates Darcy friction factor using the method in Buzzelli (2008)
      [2]_ as shown in [1]_.
  
      .. math::
          \frac{1}{\sqrt{f_d}} = B_1 - \left[\frac{B_1 +2\log(\frac{B_2}{Re})}
          {1 + \frac{2.18}{B_2}}\right]
  
      .. math::
          B_1 = \frac{0.774\ln(Re)-1.41}{1+1.32\sqrt{\frac{\epsilon}{D}}}
  
      .. math::
          B_2 = \frac{\epsilon}{3.7D}Re+2.51\times B_1
  
      Parameters
      ----------
      Re : float
          Reynolds number, [-]
      eD : float
          Relative roughness, [-]
  
      Returns
      -------
      fd : float
          Darcy friction factor [-]
  
      Notes
      -----
      No range of validity specified for this equation.
  
      Examples
      --------
      >>> Buzzelli_2008(1E5, 1E-4)
      0.018513948401365277
  
      References
      ----------
      .. [1] Winning, H. and T. Coole. "Explicit Friction Factor Accuracy and
         Computational Efficiency for Turbulent Flow in Pipes." Flow, Turbulence
         and Combustion 90, no. 1 (January 1, 2013): 1-27.
         doi:10.1007/s10494-012-9419-7
      .. [2] 	Buzzelli, D.: Calculating friction in one step.
         Mach. Des. 80, 54-55 (2008)
      '''
      B1 = (.774*log(Re)-1.41)/(1+1.32*eD**0.5)
      B2 = eD/3.7*Re + 2.51*B1
      return (B1- (B1+2*log10(B2/Re))/(1+2.18/B2))**-2